High school students with positive mental health are less likely to consume cannabis, a recent University of Waterloo study has found.

The public health study used data from 6,550 high school students in grades 9 to 12 in Ontario and British Columbia, collected from a mental-health component of a longitudinal national youth study called COMPASS. The findings suggest that marijuana prevention programs should focus on promoting mental wellbeing instead of abstinence.

“Abstinence-focused interventions targeting substance abuse have been shown to be ineffective,” said Alexandra Butler, lead author and graduate studies student in the School of Public Health and Health Systems. “Therefore, prevention strategies for youth cannabis use should aim to foster mental wellbeing among all youth, rather than exclusively targeting those experiencing mental health problems.”

One-third of participating high school respondents reported that they had tried cannabis at least once in their lifetime, and more than 3 percent were daily users. Daily users had the highest frequency of depression (65 percent) and anxiety (54 percent), current smoking (65 percent), current binge drinking (88 percent), and reported the poorest flourishing scores compared to non-users and less frequent users of cannabis. Flourishing is defined as the presence of positive mental health, including emotional, psychological and social prosperity.

The researchers also found that cannabis use for females was more likely to be sporadic and monthly, while male cannabis use was more likely to be weekly, habitual or daily. Additionally, females were more apt to report depression, anxiety, and lower flourishing levels compared to males.

“By using future waves of the COMPASS longitudinal data, we will be able to explore the impact that legalization in Canada has had on marijuana use on youth mental health and cannabis use,” said Scott Leatherdale, an associate professor of Applied Health Sciences at Waterloo.

The study, Interrelationships among depression, anxiety, flourishing, and cannabis use in youth, was published in Addictive Behaviours by Alexandra Butler, Karen Patte, Mark Ferro and Scott Leatherdale.

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